203. Remove Linked List Elements，linkedelements

203. Remove Linked List Elements，linkedelements

Remove all elements from a linked list of integers that have value val.

Example
Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6
Return: 1 --> 2 --> 3 --> 4 --> 5

代碼如下：

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode removeElements(ListNode head, int val) {
        if(head==null)
        return null;
        
        while(head.val==val&&head.next!=null)
        head=head.next;
        
        if((head.next==null&&head.val==val))
        return null;
        
        ListNode p=head;
        
        while(p.next!=null)
        {
            if(p.next.val==val)
            p.next=p.next.next;
            else p=p.next;
            
        }
        return head;
    }
}